Pc loses screen resolution in sleep modus

I have this problem with my PC where sometimes (but not always), after waking up from sleep- or slumber modus, the screen resolution is reset to something like 1024 x 728 instead of the usual 3440 x 1440. In those cases, I cannot manually reset the resolution (no other resolutions are visible in the settings), so I have to restart the PC. This always fixes the problem, but is also quite annoying ( I have to close and restart all applications…)

Does anyone know what might cause this, and how I fix it? It improved for a bit after I changed the thermal paste on my video card, but recently it became a regularly occurring problem again…

Screen: LG Ultrawide, drivers are up to date
PC: Intel(R) Core™ i7-9700K CPU @ 3.60GHz 3.60 GHz, AMD RADEON RX 590 8GB videocard. Again: drivers are up to date.

Thanks in advance for any suggestions!

I know you mention the drivers are up to date, but this does seem like a driver issue. Maybe try to completely delete and reinstall the driver? Did you open a ticket with LG support? You may want to in case it’s a known hardware problem and they can RMA it.

Maybe its a faulty Displayport cable?

That certainly seems possible. Maybe even just a loose connection?

Does it not refresh the resolutions if you power cycle the monitor?

Thanks for the answers all, and apologies for my late response: family responsibilities got in the way…

I did not check, will do so next time it happens!

Connection feels tight, but it could indeed be faulty. I will get another one and see if that fixes it!

I did, it is definitely not the drivers. But thanks for the advice on opening a ticket with LG: if replacing the cable doesn’t work, I’ll definitely try that!